We report a case of a 29 year old male who at age 25, developed a pulmonary abscess in the left lower lobe. A left lower lobectomy was performed following two recurrences on antibiotic treatment. The result of histopathological examination confirmed congenital cystic adenomatoid malformation (CCAM), a congenital disease characterized by multiple cysts resulting from adenomatous hyperplasia of the bronchial epithelia. In many cases, respiratory distress occurs during the neonatal period, and in about 80-85% of patients, CCAM is diagnosed before the age of two years due to respiratory infection. CCAM which was diagnosed in adulthood is very rare.